Aston Martin diagnostic trouble code
P1794: Battery Voltage Too High >16V
Use this reference to understand the recorded condition, confirm the available V8 Vantage or DB9 manual coverage, and follow the documented diagnostic checks before replacing parts.
- Code family
- Powertrain
- Vehicle system
- Electrical and control modules
- Manual coverage
- DB9
- Warning-lamp status
- DB9: MIL
What Aston Martin code P1794 means
Battery Voltage Too High >16V
DB9 preliminary diagnostic manual · section 2-278
Manufacturer fault-analysis procedure
Manual fault definition
P1794 - Battery voltage too high - above 16 volts
Auto Transmission only.
Auto Transmission only.
Test sequence and decision path
1. Connect the WDS and record all logged DTCs.
Ensure that P1794 is logged.
2. Key on, start the engine. Run the engine at
approximately 2000rpm and switch on the headlamps. Measure the battery voltage from the Jump
Start terminal to chassis ground.
The battery charge voltage should be
approximately 13.8 volts.
If the charge voltage is about 13.8 volts, go to
step 3.
If the charge voltage is too high, around 16 volts,
service the charging system as necessary. Clear
the P1794 code and repeat the charging voltage
check. to ensure that the problem is resolved.
3. Check the vehicle history for other indications of
overcharging (Overvoltage message on instrument panel and possible frequent failure of tungsten filament bulbs).
If there is no history of overvoltage effects, go to
step 4.
If there is a history of overvoltage effects, rerun
the checks in step 2 several times checking for
intermittent open or short circuit porblems.
Service the wiring as necessary and run a KOER
test to ensure that the porblem is resolved.
4. Service the charging system as necessary. Clear
the P1794 code and run a KOER test to ensure
that the problemn is resolved.
5. If the charging circuit is serviceable, access the
transmission connector C0932 and check for +12
volts between C0932-14 and C0932-13 on the
harness connector with the ignition on. Repeat
the check from C0932-14 to C0932-16 to confirm that both ground connections are good.
If any defect is identified, service the circuit as
necessary and retest to ensure that the problem is
resolved.
Open the corresponding manual page for wiring diagrams and figures
Ensure that P1794 is logged.
2. Key on, start the engine. Run the engine at
approximately 2000rpm and switch on the headlamps. Measure the battery voltage from the Jump
Start terminal to chassis ground.
The battery charge voltage should be
approximately 13.8 volts.
If the charge voltage is about 13.8 volts, go to
step 3.
If the charge voltage is too high, around 16 volts,
service the charging system as necessary. Clear
the P1794 code and repeat the charging voltage
check. to ensure that the problem is resolved.
3. Check the vehicle history for other indications of
overcharging (Overvoltage message on instrument panel and possible frequent failure of tungsten filament bulbs).
If there is no history of overvoltage effects, go to
step 4.
If there is a history of overvoltage effects, rerun
the checks in step 2 several times checking for
intermittent open or short circuit porblems.
Service the wiring as necessary and run a KOER
test to ensure that the porblem is resolved.
4. Service the charging system as necessary. Clear
the P1794 code and run a KOER test to ensure
that the problemn is resolved.
5. If the charging circuit is serviceable, access the
transmission connector C0932 and check for +12
volts between C0932-14 and C0932-13 on the
harness connector with the ignition on. Repeat
the check from C0932-14 to C0932-16 to confirm that both ground connections are good.
If any defect is identified, service the circuit as
necessary and retest to ensure that the problem is
resolved.